Bharatpur sanctuary under threat from alien species: Report

NEW DELHI: An international study that used a new method to categorise risk of biological invasions in world heritage sites has found that Rajasthan’s Keoladeo National Park, formerly known as the Bharatpur Bird Sanctuary, is facing a “high threat” from invasive

alien species

, with as many as 14 such species thriving in the world heritage site.


Keoladeo was identified as facing 'low threat' in the invasive alien species threat level indicated in the 2017 IUCN World Heritage Outlook — the first global assessment of natural world heritage. But in a new study published in the journal Biodiversity and Conservation, researchers have categorised the site as facing 'high threat’ from biological invasions.

The study noted that efforts to manage invasive plant species were taking place in Keoladeo but warned that threats are increasing and the site is likely to be incapable of facing future challenges.

The researchers consulted with experts from Dehradun-based Wildlife Institute of India (WII) and combed through literature while using a newly developed method of risk assessment to identify 14 species that can be considered to be invasive in the park.

African

catfish

, which is alien to the area is being removed from the area

The new approach identified plants as the most common invasive species (nine) followed by two types of fish — common carp and African catfish. Two mammals — bovine (Bos taurus) and rhesus monkey (Macaca mulatta) — and a moth species (Parapoynx diminutalis) were also identified as invasive.

“Most of these species are known to cause high threats and impacts elsewhere in India and in many regions of the world,” lead author Ross Shackleton, faculty member at the University of Lausanne (Switzerland), told TOI. “While species like the Clarias gariepinus (African catfish) and Prosopis juliflora (a tree) are being managed, not much progress has been made. This is also the case in many protected areas which face threat from invasions despite management,” he said.

The new method developed by Shackleton and his team lays a step-by-step procedure to collect information and to report on pathways through which alien species are spreading, assessing their impact and management as well as predicting future threat and management needs, finding the status of knowledge and gaps and assigning an overall 'threat score' to the protected area.

Formal surveys on the site could reveal more invasive species, the researchers said. Professor K Sivakumar, head of the department of endangered species management at WII, who lent his insights to the study said there could easily be more than 50 invasive alien species on the site. “We have never done a detailed study to identify invasive species or the routes through which they are spreading,” he said.

Sivakumar said not enough attention has been paid to invasive alien species even though the country needs a policy or an invasive alien species Act to deal with them on war footing and reduce the threat to biodiversity. “Most tiger habitats in the country have been invaded by lantana (a shrub) while common water hyacinth (Eichhornia crassipes) is choking our wetlands. Another major threat is P juliflora trees which encroach on the wetland,” he said.

While the latest framework used in the new study would help researchers, for the management to implement it on the ground we need clear policy guidelines, said Sivakumar.

Mohit Gupta, deputy conservator of forests (DCF), wildlife, Bharatpur, admitted that invasive alien species are among the biggest threats to the park ecosystem but added that their management was a long-term process. “Invasive alien species is an important aspect of park management right now. We are removing invasive species every year but this is more of a symptomatic treatment and a short-term measure. So as a long-term approach, we have renewed our focus on reviving the basic ecology and natural processes of the park."